JP2816653B2 - Soil compaction and consolidation methods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in works for compacting soil in civil engineering and construction work, for example, backfilling of works, embankment of roads, backfilling of structures, embankment of rivers, land reclamation, land reclamation, etc. It relates to a method of compacting and compacting soil.

[0002] The meaning of each term used in the present specification is as follows.

[0003] Optimum water content: water content ratio at which density is maximum Fine particles: soil particles having a particle size of less than 75 μm HLB: hydrophilic / hydrophobic balance, HLB = 20 (MH)
/ M), where MH: molecular weight of hydrophilic group portion, M: overall molecular weight Viscous soil: contains fine particles having a particle size of less than 75 μm by 50% or more, has no dilatancy phenomenon, and has a medium to high dry strength. Say things.

[0004] Silt: A substance containing 50% or more of fine particles having a particle size of less than 75 μm, having a remarkable dilatancy phenomenon and low dry strength.

[0005] In this specification, the amount of the surfactant added to the soil is based on the soil volume after compaction unless otherwise specified.

[0006]

2. Description of the Related Art The purpose of compacting soil in backfilling of works, embankment of roads, backfilling of structures, embankment of rivers, land reclamation, land reclamation, etc. is as follows. It is stable throughout the service period and exhibits the required supporting force. This is because, if the compaction is insufficient, the degree of saturation of the soil changes due to the flooding, causing a large destruction of the settlement, which may cause a fatal damage to the above-mentioned structure or the like.

Conventionally, as a method of compacting soil containing fine particles so that the change in the degree of saturation upon flooding is reduced, a method of compacting the soil by adjusting the soil to a water-containing state of an optimal water content ratio or more has been performed. However, even in situations where modern compacting machines can be used and construction using thin layer compaction is possible, compacting takes a lot of trouble and time. Therefore, in the current construction method, in a state where compaction is inadequate, a method is adopted in which the work is left for a long time after tentative completion, or a part that has settled during the service period is repaired.

An object of the present invention is to provide a soil compaction / consolidation method capable of solving the above problems.

That is, an object of the present invention is to provide a compacting machine which can perform sufficient compacting easily and in a short time by using a compacting machine conventionally used, and can minimize settlement after completion of construction. An object of the present invention is to provide a consolidation / consolidation method.

[0010]

The present invention solves the above-mentioned problems by the following constitution.

The method for compacting and compacting soil according to the present invention is generally
The Batch specifically, there soil upon which compaction, consolidation, the admixing surfactant to the soil having a free hydration promoting action and between soil particles friction reducing effect of the soil particles interstitial water, specifically
Solves the problem of the present invention by each configuration of claims 1 to 3.
Is what you do .

According to the first aspect of the present invention, there is provided a method for compacting and compacting soil according to the present invention.
A compaction / consolidation method characterized by adding approximately 1 to 2000 g (0.0001 to 0.2 W / V%) of a nonionic surfactant or the like to 00 L (1 m ³ ) and mixing.

According to a second aspect of the present invention, there is provided a method for compacting and compacting soil according to the present invention.
About 1 to 2000 g (0.0001 to 0.2 W / V%) of a combined surfactant mainly containing a nonionic surfactant or the like and containing an ionic surfactant per 00 L (1 m ³ ).
It is characterized by being added and mixed.

[0014] Compaction-compaction method of the soil of the present invention according to claim 3, in compaction, consolidation methods soil according to any one of claims 1-2, unwinding divided soil a plurality of times, When the compaction is repeated, a surfactant is sprayed on the surface of the extracted layer every time the powder is extracted, and the surfactant is added to and mixed with the soil.

[0015]

[Detailed description of means]

(1) The soil compaction and compaction method of the present invention is a method of compacting and compacting soil in backfilling work, road embankment, backfilling structures, river embankment, land reclamation, landfilling, etc. in civil engineering construction work. Is assumed.

The term "soil" used herein includes not only coarse-grained soil such as sand and gravel, but also fine-grained soil containing a large amount of fine-grained soil and construction-generated soil generated in civil engineering and construction work.

(2) Basically, a surfactant having a function of accelerating free water formation of pore water in soil particles and a function of reducing friction between soil particles is added to and mixed with soil. Therefore, depending on the soil, an ionic surfactant having no such action in relation to the soil is excluded only in relation to the soil (see Comparative Examples 1 and 2).

The amount of the surfactant to be added varies depending on the soil type and the type of the surfactant.
Against (1 m ^3), substantially the surfactant 1~2000g
(0.0001 to 0.2 w / v%),
0.001 w / v% to 0.1 w / v%, more desirably 0.01 to 0.05 w / v% is added and mixed.

If the surfactant content is less than 0.0001 w / v%, it is difficult to obtain rapid compaction and compaction of the soil,
Even if it exceeds 0.2 w / v%, no further effect can be expected.
In addition, the cost increases.

The mixing method is as follows: a surfactant is converted into an aqueous solution or an aqueous dispersion of an aqueous dispersion or solid, and mixed by a concrete agitator wheel, a backhoe, a soil mixer, a screw conveyor, a scraper, or the like; Can be done in a way.

However, the following spraying method is desirable from the viewpoint of easy addition to a large amount of soil.

When the soil is repeatedly extracted and compacted a plurality of times, a surfactant is sprayed on the surface of the extracted layer for each extraction, and the surfactant is added to the soil and mixed. It is advisable to perform the break-in as needed. No special mixing method such as the mechanical mixing method described above is required, and the drug can be easily added on site.

The soil produced in this manner can be used as conventional road rollers, tire rollers, vibrating rollers, vibrating compactors, tamping rollers, tampers (rammers),
The compaction method using a bulldozer, etc. enables the compaction in a short period of time for backfilling structures, embankment of roads, backfilling of structures, embankment of rivers, land reclamation, land reclamation, etc. in civil engineering and construction work. The amount is significantly reduced.

(2) As the above-mentioned surfactants, the following types of surfactants can be used alone or in combination. In particular, among these, nonionic surfactants and polyethylene oxide are desirable. This type of non-ionic surfactant is less susceptible to soil ionicity and the like, as shown in the examples below, and can be used in combination with other surfactants to achieve stable rapid compaction. Shows compaction effect.

Nonionic surfactant: polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene, oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol Fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine,
Alkyl alkanolamides and the like.

Anionic surfactant: fatty acid salt, alkyl sulfate salt, alkyl benzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfosuccinate, alkyl diphenyl ether disulfonate, alkyl phosphate, polyoxyethylene alkyl or alkyl allyl Sulfate, Naphthalenesulfonic acid formalin condensate, special carboxylic acid type and sulfonic acid type polymer surfactant, polyoxyethylene alkyl phosphate, metal soap, etc.

Cationic and amphoteric surfactants: alkylamine salts, quaternary ammonium salts, alkylbetaines, amine oxides and the like.

Others: polyethylene oxide (molecular weight: 500 to 6000, preferably 1000 to 500)
0), water reducing agents, air entrainers, fluidizing agents and underwater separation inhibitors used in concrete admixtures, natural polymer surfactants such as polysaccharides and proteins, etc. (3) These surfactants are used in cements. There is no problem even when used in combination with quicklime, slaked lime, dolomite and the like.

However, since the treated soil becomes strongly alkaline, when it is used as a medium base for plant growth which prefers a neutral or weakly acidic medium, mineral acids such as sulfuric acid, nitric acid and hydrochloric acid, or these mineral acids And organic acids such as acetic acid, citric acid, humic acid, nitrohumic acid, or the salts thereof,
Further, nitrogen fertilizers such as ammonium sulfate, salt ammonium, ammonium nitrate and urea, potassium fertilizers such as potassium sulfate and potassium chloride, and phosphorus fertilizers such as lime superphosphate and ammonium phosphate may be appropriately added to and mixed with the above soil.

In addition, calcined minerals such as gypsum, granulated blast furnace, fly ash, vermiculite and perlite,
It is also possible to add and mix inorganic fibers such as rock wool and polymer fibers such as polyester, polypropylene, polyethylene and vinylon. Also, granular styrofoam may be mixed to reduce the weight of the soil.

[0031]

The operation of the soil compaction / consolidation method of the present invention is presumed to be as follows.

The soil engineering characteristics of soil are greatly affected by the coagulation / dispersion effect acting between soil particles. It is well known that the coagulation and dispersing action between soil particles varies depending on the charge and the adsorbed layer. The adsorption layer effect is changed by lowering the interface free energy and forming a hydrophilic adsorption layer on the soil particle surface.

According to the present invention, the adsorbent layer is modified with a surfactant to accelerate the compaction of the soil and promote the compaction settlement.

The action of the surfactant shown in FIG. 1 will be described. The greatest effect is that the adsorption layer existing between the soil particles shown in the upper part of the "microscopic effect" in the figure becomes thinner. As a result, the free water increases and the effective gap expands, consolidation and settlement are promoted, and the compaction can be rapidly performed by the reduction in the friction between the soil particles shown in the middle stage. With these, it is possible to shorten the time to the maximum density state showing the “macroscopic effect” in the figure.

[0035]

Examples and Comparative Examples Next, examples performed together with comparative examples to confirm the effects of the present invention will be described. However, the present invention is not limited to these examples.

(1) Construction method: An outdoor experiment was carried out assuming an actual burial pipe backfilling work. The soil used is the soil generated from construction, and its type is shown in Table 1. Table 2 shows the types of surfactants, etc., FIG. 2 shows the procedure of the experiment, and FIG. 3 shows the state of the experiment.

The procedure of the experiment was as follows. A stirring / mixing water tank having a stirrer and a pump was installed on a truck, and 25 L of an aqueous solution whose concentration was adjusted so as to have an addition amount shown in Table 3 was prepared. Was sprayed. Thereafter, a rammer (self-weight: 63 kg, nominal contact pressure: 0.075 kgf / cm ² , size of contact surface: 33 × 3)
3 cm). The backfill layer thickness was 35 cm.

(2) Evaluation method: The effect of the surfactant was measured by measuring the settlement of the ground surface at the compacted place, and the time required for the settlement to converge and the final settlement amount were used. When the time required for the settlement to converge was shorter than that when no addition was made, it was determined that there was a rapid compaction effect, and when the value of the final settlement amount was small, it was determined that there was a rapid compaction effect.

Table 3 shows a list of the results of the evaluation test.

(Examples 1 to 3) The same nonionic surfactant was added while changing the amount and soil quality. As a result, the time required for the settlement to converge was shortened and the final settlement amount was smaller than in the case where no addition was made. Therefore, the improvement effect was observed regardless of the type of soil. In Example 1 with the smallest addition amount, no particularly remarkable effect was observed, and in Example 3 with the largest addition amount, the effect was lower than in Example 2.

Examples 4 to 6 Nonionic surfactants were added in the same amount and in soil. As a result, the time required for the settlement to converge was shortened, the final settlement amount was reduced, and an improvement effect was observed as compared with the case where no addition was made.

Examples 7 to 11 Ionic surfactants and polyethylene oxide were added to different soils in the same amount. As a result, the time required for the settlement to converge was shortened, the final settlement amount was reduced, and an improvement effect was observed as compared with the case where no addition was made.

(Comparative Examples 1-2, Examples 7.9) Comparative Example 1
In this example, an anionic surfactant was added to soil B (montmorillonite type). As a result, the time required for the settlement to settle was longer than in the case where no addition was made, and the final settlement amount was not reduced. Similarly, in Comparative Example 2, a cationic surfactant was added to the soil C. As a result, the time required for the settlement to settle was longer than in the case where no addition was made, and the final settlement amount was not reduced.

Corresponding to Comparative Examples 1 and 2, in Examples 7 and 9 in which a surfactant was similarly added to soils of different soil types, an improvement effect was observed.

Therefore, it is presumed that the ionic surfactant has different improvement effects depending on the type of soil, that is, it does not sufficiently exert the action of promoting free water of pore water in soil particles and the action of reducing friction between soil particles. You.

Example 12, Comparative Example 3 In the case of Example 12 in which a nonionic surfactant was mainly used and an anionic surfactant was used in combination, a nonionic surfactant was mainly used and a nonionic surfactant was used. As in Comparative Example 3 in which a surfactant was used in combination, a phenomenon in which the improvement effect was reduced due to a difference in soil quality did not occur.

(Examples 13 to 15) When a cationic surfactant, an amphoteric surfactant and polyethylene oxide were used in combination with a nonionic surfactant as a main component, the settlement was converged as compared with the case where no surfactant was added. The required settlement time was reduced, the final settlement was reduced, and a stable improvement effect was observed regardless of the difference in soil quality.

[0048]

As supported by the embodiment, according to the soil compaction / consolidation method of the present invention, compaction work in civil engineering construction work requiring time and labor can be completed in a short time. . In addition, since the amount of settlement also decreases,
Repair work can be minimized.

Furthermore, since it is particularly effective for soils containing a large amount of fine particles, it leads to an increase in the types of useful soil materials, and is effective in reusing construction-generated soil which has become a social problem. Is also effective.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the action of a surfactant in the present invention.

FIG. 2 is a construction method (experimental procedure) in an embodiment of the present invention.
Showing process chart

FIG. 3 is an explanatory diagram showing a backfilling method (experimental state) in an embodiment of the present invention.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 3/02

Claims (3)

(57) [Claims] 1. The soil volume when compacting and compacting soil
For 1000 L (1 m ³ ), nonionic surfactant
Or polyethylene oxide (hereinafter referred to as “nonionic surface active
Etc. " ) Of about 1 to 2000 g (0.0001
Compaction characterized by adding and mixing
And consolidation method. 2. The soil volume when compacting and compacting soil.
For 1000 L (1 m ³ ), nonionic surfactant
Combined surfactant mainly containing ionic surfactant
Approximately 1 to 2000 g (0.0001 to 0.2 W / V)
%) A compaction / consolidation method characterized by adding and mixing. 3. The soil tightening according to claim 1,
Extracting the soil in multiple steps in the consolidation / consolidation method
・ When repeating compaction, apply surfactant every time
Sprinkle on the surface of the layer that came out and add the surfactant to the soil
-A compaction / consolidation method characterized by mixing.